Heat the oven to 350 degrees. Line a baking sheet with a
silpat mat or parchment paper.

In a medium bowl cream the butter and sugar together until
light and fluffy. Add the egg and beat until well incorporated. Stir in the
vanilla.

Sift in the flour, baking soda and cream of tartar.

Mix until all the ingredients are fully combined.

The dough will be a little sticky, but that’s OK.

In a small bowl combine the sugar and cinnamon.

Divide the batter into 4 equal amounts. Roll the dough into
the cinnamon sugar. I find if you put the dough into the sugar and then roll
it, this seems to help it not stick to your hands too badly. If you had time
you could refrigerate the dough for 30 minutes that would help too.

Place the dough balls onto the prepared baking pan.

Press just slightly to flatten the tops, don’t press too
much the cookies will spread out on their own.

Bake for 9-11 minutes or until the edges are crisp and the center
is just set.

Let the cookies cool on the pan for 5 minutes before
transferring them to a wire rack to cool completely.

Now I dare you not to eat all 4 of these beauties at one
time. They are JUST THAT GOOD! They are so soft and chewy, the perfect Snickerdoodle.